Method of treating welds and product



April 8, 1941. R 5 SPAULDING 2.237.716

METHOD OF TREATING WELDS AND PRODUCT Filed June 15, 1940 v whichordinarily metal members.

Patented Apr. 8, 1941 METHOD OF TREATING WELDS AND PRODUCT Ralph E.Spaulding,

Jacksonville, Fla., assignor to Aetna Iron & Steel 00., Jacksonville,Fla, a cor- I poration of Florida Application June 15, 1940, Serial No.340,858

1 Claim.

, This invention relates to a method whereby electric or gas fusionwelds, either autogenous I -or with filler metal, may be made inavoidance of locked-in stresses or shrinkage stresses produce warpage inthe united In welding, the application of intense heat to a localizedarea causes that area to expand. Expansion of this highly heatedlocalized area cannot take place in a normal manner, that is, in alldirections in accordance with the temperature change times thecoeiiicient o thermoexpansion, and, therefore, deformation of the weldarea occurs. Both the modulus of elasticity and the yield point are verylow at high temperatures, thus facilitating its deformation. Acorresponding thermal expansion cannot quickly take place in the membersbeing welded together, due to the larger areas of relatively coldermetal surrounding the weld area and, therefore, the deformation resultsin the shorting of the axis of this area. On this highly heated area iscus-' tomarily deposited weld or filler metal in liquid form, this addedmetal becoming an integral part of the highly heated base metal.

As this area (base metal plus filler metal, if any), cools to thetemperature of the original piece, it attempts to shrink in alldirections in accordance with the natural law of thermal contraction.However, as heretofore mentioned, this area has undergone deformationand its axis, longitudinally of the weld, has become permanentlyshortened with respect to the larger areas of parent metal. That is tosay, the unit axial length of the weld area in its highly heated stateis the same as the normal unit axial length of parent metal at roomtemperature. As the entire areas become again of one uniformtemperature, the weld area is found to be under very high stress intension and the surrounding parent metal is found to be under stress incompression, the relation of the respective tension and compressivestresses being determined by the inverse relative areas of the weld zoneto the remaining areas. The result is locked-in" stresses accompanied bya shortening in the length of the material where welded, with consequentwarping of the assembly.

To prevent this tendency to distort, I treat the weld area. duringoriginal cooling, that is to say, while it is trying to shrink and isprevented from doing so by the superior bulk and strength of therelatively colder adjacent metal. This treatment comprises subjectingthe welded area to compacting force which may be applied in variousways. The Welded body may be vibrated as a whole. Preferably, vibratorycompressive force is applied to the weld face, as by a pneumatic hammer,or pressure may be otherwise applied. In the treatment of an elongatedweld in the use of a pneumatic hammer, the treatment is progressivelongitudinally of the weld. The

treatment is applied while the weld area is still in plastic stateduring original cooling and is not necessarily continued during theentire cooling period, but only during such part of the period as may befound necessary to accomplish the desired result, namely, to elongatethe weld zone so that upon cooling it will have the original length ofthe base metal. The compacting action resulting from the hammering,pressing or vibrating treatment causes the weld area to do what itcannot do by itself, namely, to undergo a deformation counter to thatwhich took place .while the weld was being formed. This beingaccomplished, there remain no locked-in" stresses of any consequence,nor is there any shrinkage or warpage of the welded assembly.Additionally, tests show that welds treated in accordance with theinvention are stronger than untreated welds. The treatment may beapplied to any welds on any metals which may be effectively united byfusion welding.

In the accompanying drawing I have shown the application of theinvention in various situations involving the formation of a weldedjoint between adjacent lateral edges of elongated members, here assumedto be of steel.

Figure 1 illustrates a manner of treating a weld of a built-up I-beam,the beam being shown in end elevation.

Figure 2 is an enlarged partial view of the base portion of thestructural member of Figure 1 and illustrates the heat condition in theweld zone.

Figure 3 is a sectional view of deck plates welded to a girder inaccordance with the prior practice.

Figure 4 is similar to that of Figure 3, but showing the application ofthe present invention.

Figure 5 is a transverse section of a hollow beam formed of channelswith treatment in accordance with the present invention.

Figure 6 is a sectional view of an assembly comprising angularly relatedplates with welds treated in accordance with the present invention, and

Figure 7 is a transverse section of a built-up L- beam constituted. byautogenously welded elements with treatment in accordance with thepresent invention.

Referring to the drawing, and first to Figures 1 and 2, referencenumeral i designates an I- beam including a web ii and top and bottomflanges i2 and i3. Reference numeral i i designates filler metal whichas shown in Figure 2 forms an. integrated zone It with the adjacent basemetal this zone being indicated as all; yellow or orange heat andextending half-way across the web ii. The zone i5 is surrounded by azone 66 at red heat. These heat conditions are merely illustrative andit is to be understood that the new method can be carried out at anytime during original cooling while the weld zone is in plasticcondition. A pneumatic hammer H has a head it with a fiat end face it ofcircular contour having a diameter somewhat less than the width of theweld face. The hammer is traversed longitudinally of the weld area,following the welding operator, the head striking the face of the weldin overlapping strokes. The vibratory efiect compacts or settles andelongates the weld area so that upon cooling of the whole, thelongitudinal axis of the base metal in this area is the same in lengthas before the welding operation. In this manner locked-in" stresses andconsequent shrinkage and warpage are avoided. Desirably, weld H3 issimultaneously treated. Ordinarily the welds are longitudinallycontinuous.

The welded assembly is distinguishable by the fact that the fillet has asmooth face'as the result of the vibrating action, and, as above stated,the weld is appreciably stronger than one formed quently flattened. Inthe practice of the present invention, as illustrated in Figure 4, theaction of hammer 2 not only finishes the filler metal 25 flush with thedeck plates, but also prevents any tendency of the plates to bulge.

In Figure 5 reference numerals 26 and 21 designate channels weldedtogether to form a hollow beam, the welds incorporating filler metal asat 28 and id and the weld areas being preferably simultaneously treatedas by the hammers 3d and 3!.

In Figure 6 reference numerals 32, 33 and 3d represent plates united inangular relation by welds 35 and 36, the latter being shown asundergoing treatment by a hammer 32. The avoidance of warping in shapesof this nature, as accomplished by the practice of the presentinvention, is particularly important in this instance, since the warpagewhich would occur in the absence of treatment is extremely diiiicult 'tocorrect.

In Figure 7 reference numerals 3i and 38 designate plates unitedautogeneously in rectangular relation by a weld zone 39 which is treatedin accordance with the present invention by a hammer it having a headill with angular faces at the same angle as the angle between members 3iand 38.

The drawing, of course, indicates only a few of the many possibleapplications of the invention in the production of welded assemblies.The invention extends to the treatment of all welds of substantialextent and to the resulting in the absence of the new treatment. Thereare,

therefore, present the outstanding advantages of greater strength,absence of locked-in stresses, the retention of original length, and theavoidance of warpage and of a consequent straightening operation.

Figure 3 shows deck plates 2% and 2! welded together and to the top;flange of an I-beam 22 through a fillet 23in acordance with priorpractice. The fillet protrudes upwardly, necessitating a finishingoperation. Furthermore, during cooling the plates become bowed asindicated by the dot and dash lines and' have to be subseproducts.

I claim:

In the method of forming an elongated joint between two elongated steelmembers having elongated adjacent edges to be joined, said methodcomprising moving a welding electrode along said edges to form a weld,the step which comprises following the electrode along the weld withcompacting means acting on the weld area while the latter is stillplastic under the original heat of welding, whereby to elongate the weldarea and thereby prevent shrinkage stresses in the welded assembly.

RALPH E. SPAULDING.

